Compound metallic article.



G W. DAVIS.

COMPOUND METALLIC ARTICLE.

APPLIOATION FILED 1 312.15, 1913. RENEWED NOV. 24, 1913.

1,1 M 729, Patented June-30, 19%

I WITNESSES:

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GOMPOUND 'METALIJIG ARTICLE.

memes.

Specification of Letters Patent. Patented- June 30; 19i4 Application mearebruar is, 1913, SerialNo. 748,219. Itenewed-November24, 1913. s mi No. 802,801.

To all whom it mag concern Be it known that I, CHARLEs W. DAVIS, residing at Edgeworth, in the county of Allegheny and State of Pennsylvania, a citizen of the United States, have invented or discovered certain new and useful Improvements in Compound Metallic Articles, of

which improvements the following is ,a

' I roll pass which is rectangular in crosssecspecification.

My invention relates to "improvements in the methods of forming compound metallic articles, and specifically to improvements in that method of formation which involves inclosing or incasing a bodyof one metal within an envelop of another metal, and elongating or extending a blank so compounded, the component bodies of-metal being both of them, at the time when the blank is assembled, at temperatures below their'melting points.

While my invention is not limited-to specific metals, nor to a specific article, I shall describe' it in its application to the production of compound metallic wire having a core of steel, and a covering of copper. Thismaterial is now commercially produced by a method which involves-the surrounding of a core of steel with a sleeve of copper, both metals being in solid state, and in then bringing the blank so compounded to rolling temperature, and rolling it to rod form, and subsequently drawing the rod to wire. It is a matter of first importance in this material that the union of the two metals, which is effected in the early stages of the rolling operation, be most intimate, and it is -appar-' ent that the existence of an appreciable space between the adjacent'surfaces of the copper and the steel, prior to that point in the-operation where intimate union is effected, is undesirable; or, stated in'other words, it is desirable to bring the surfaces of the components into the closest ossible contact in order to get the best resu ts. It willbe understood that in the specific case ofcopper enveloping steel, the ditficulty due to the presence of any space, or rather-the problem of eliminating, so far as possible, -the space between the surfaces, is aggravated bythe fact that the coefficients of expansion of these twometals are not alike, and that cop-- space interval between the adjaeeHtQsnrf-aees j may be at a minimum, in the subsequent heating operation preparatory to rolling the space will necessarily be enlarged. It will.

tion, the first efiect of rolling is to compress the adjacent surfaces together at diametrically opposite points, and at the same time to cause or tend .to cause theseparation of the surfaces at intermediate points. It will be understood by those familiar with the practice that, inasmuch as in succeeding roll passes the article under treatmentis shifted by turning on its axis ab out there are successively produced strains which tend to open the interstices between the component bodies, as well as strains which tend to close them, and it. is a fact that gaps are at times produced. lhe presence of appreciable spaces between the adjacent surfaces of the-components is undesirable, articularly at the temperature of rolling, because the resence ofoxid on the adjacent surfaces is mim'ical to intimate union, and because at the elevated temperature of rollinglthe metals. are peculiarly liable to oxidation, and be cause the intrusion air into such spaces as may exist is a cause which may produce oxi dation.

My invention may be stated in general terms to consist of a method of forming compound metallic bodies in which a core of relatively coldmaterial is surrounded by a covering ofrelatively hot material, and the blank. thus formed is subsequently brought to a temperature proper forreductionor extension.

Specifically in case of copper-icladsteel A wire, my method is employed in inclosing the core ofsteel at relatively low temperature-in asleeve of copper at relatively high temperature (both bodies 'of metal being at temperatures lower than the several melting points and then subjectmg the compound bla to the usual operations of reduction. In initially uniting the compe nents, I may practise oneor, another of several expedients. "For example, the existing practice is to properly prepare the steel core and the copper sleeve, and then to drive-the sleeve over he-wore Ineagilapt na-my +inbring the whole to at 25.

ventionto this procedure, 1 preferably employ a copper sleeve and a steel core of such relative sizes that while they may not be united when both are at normal atmospheric temperatures, the enlargement of the copper sleeve under a permissible increase of temperature will be suflicient to permit of assembling them by inserting the core within the sleeve. When the components have been properly prepared, I heat the copper sleeve (preferably in a non-oxidizing atmosphere) to a point lower than the meltin point of the copper, but to a point at which it will be so enlarged as to permit the introduction within it of the previously prepared steel core,'-while the latter is at a lower and (as ordinarily will be the case) at substantially atmospheric temperature. I then brin the two bodies together, usingif found esirable such appliances as are ordinarily em ployed in the existing practice. I then allow the temperature of the combined bodies to be equalized, that is, to say,

'mospheric temperature, or to substantially atmospheric temperature,

or else I place the blank, formed by bring-- mg the two bodies together,1in the furnace where it is heated preparatory for rolling,

and keep it there until core' andsleeve are together brought to rolling temperature.

' Whether this equalization of temperature be perature, or by placing by bringing the whole to atmospheric temthe blank in a furnace where the core will be heated until of a-uniform temperature with the sleeve, the

' effect will be the same, namely, to cause the operating action of and shapin temperature, than-"the melting point of copper.

. to the opposite efiect, will either overcome, or reduce to a minimum, the tendtise'd.

"sleeve to bind closely upon the .core, or the core to bind closely within the 'sleeve, so as to diminish to, or near the point of elimination, any s ace whatever between the contacting sur aces. Even I though in the bringing of the blank to rolling temperature, the higher coefficient of expansion of copper will tend to the creation of axspace'bee tween the adjacent surfaces, nevertheless'the ste in the practice which I have now described as, my invention, tending as it does wholly ency to separation.

I have in the foregoing passage described one manner of bringing the components together One method of forming. copper tubes which is now commercially practised is to shape the tube from a block of copper. by the 00-.

a perforating mandrel- -The copper, when unrolls. operation, is at relativelyhigh though ata'temperature lower Instead ;a mandrel sub- I may shape the def-going this of shaping such a tube upon sequently tolbe withdrawn, tube upon the core of I either .a further safeguard against air while the blank is under treatment.

in which my invent-ion may be p'rac: Another mode of assembling is this in, forms one of ished article, and in this case by employing the core of steel at relatively low temperature, my invention may be enjoyed as will be understood from the foregoing description. I Still another method of forming copper tubes is what is known as the extrusion method in which a body of copper, heated to a point lower than the melting point of copper, is forced by pressure throu h an orifice, in which orifice is a central ie or mandrel,a tube of copper being in this op- .eration forced out through the orifice. I

may practise my invention by having the tube, as it is extruded from the forming machine, pass'over and surround a core of relatively cold steel, and in this case also it will be understood that the characteristic feature of my invention will be employed. In each of these cases 'it will be understood that the benefits of my innovation of operation will be realized when it comes to the heating and extending operation. 5

' After the blank'has been assembled by any the components of the finone. of the three Ways which I have described, or. in any other alternative way, the ends of it may, if desired, be .painted or coated with-a preparation of silicate of soda and ground asbestos, according to the practice now inluse. Such coating is intended as the ingress of While I'have up to this point been careful to describe my invention as applicable to the production of a definite article, namely, copper-clad steel wire, it will be understood that it is broadly applicable to the production of .articles co pounded of other materials than copper an steel, and to articles of other form than that of wire, that is to say, it is broadly. applicable to the forming ofcom-' pound metallic articles produced by forging and reducing operations from blanks in which one body of metal increases another body of metal. 1 I

a To the'essential portion of my rocess of preparation of the blank which I ave now described, I may add another step, and thisstep consists in providing surfaces of contact between steel and co periat. or near theopposite ends of the bla s-as a whole, .these surfaces of contact being so arrangedand.

disposed that further treatment of-the article after it has been assembled will in conse uence of the difierence in thermal expansion'of the component bodies in a longitudinaldirection effect a binding engagement of 7 surface upon surface, to tive-seal against the ingress of or circulation of-air in any seam or gap between the coppier and the steel. i--In t 1 is a view in longitudinal section is respect. my mve' n- I tlon lsillustrated in the accompanying drawsteel whichremaining form a more .efiecand elevation of the assembled blank; Fig. 2 is a view of like nature on a larger scale than Fig. 1 of a portion of the assembled blank, illustrating more clearly and somewhat diagrammatically the matter of the seal referred to; and Fig. 3 is a view similar to Fig. 2, illustrating a minor modification.

In the several figures corresponding parts bear the same numerals.

The steel core of the blank is indicated at 1 (1), the copper sleeve at 2 (2 Referring first to Fig. 1, it will be seen that the steel core is made somewhat longer that the copper sleeve, and that near its opposite ends and at proper positions are cut V shaped circumferential grooves. Into these V-shaped circumferential grooves the edges of the copper tube are shown to be turned. The turning in of the edges of the copper tube in this manner may be efi'ected by peening or spinning or otherwise.

In Fig. 3 the alternative consists in efiecting an end to end contact of steel with cop-- per not by turning the copper into a groove in the steel, but by upsetting theends of the slightly protruding core against the ends (shown to be properly beveled) of thecopper sleeve.

Returning now to the operation already described, let it be understood that a steel core of proper length and provided with grooves such as are illustrated in Fig. 1, and while cool, be introduced within a heated copper sleeve 2, and let it be understood that the assembled parts have thereafter been brought to atmospheric temperature. The copper sleeve will then lie closely upon the steel core. At this stage of the operation the edges of the copper sleeve are peened or spun into the previously formed grooves in the steel core so that the assembled blank will then appear as it is illustratedat Fig. 1. Thereafter, and in the further progress of the operation already described, in consequence of the greater coefficient of expansion of co per, there will be a binding engagement ongitudinally of surface upon surface, the edges of the copper sleeve .binding against the outer walls of the grooves into which ithas been shaped, thus affording a seal against the ingress or circulation of air, either in such minute space as may exist between the component metals while in blankv form, orin such small gaps as may form themselves when the article is under treatment in the rolling mill. These surfaces of contact are indicated at a, a in Figs. 1 and 2. Like surfaces of contact, indicated by the letter 6, exist in the case of Fi 3, the contact having in this case been .e ected by the up-setting of the ends of the steel core; andthe effect is the same, namely, that, by virtue of the relatively greater coefficient of expanion of copper, the contact effected at b is made more effective by compression. The

seal so effected over transversely disposed" contacting surfaces may, if desired, be made i the more impervious, by the'application to I the surfaces of contact at the time they are shaped to engage one another, of a preparation of silicate of soda or other refractory fluid. Such an application of a third body ,isindicated in Fig. 2.

"I claim herein as my invention:

1. The method herein described of forming compound metallic articles, which consists in applying to a body of metal while the said body is' in solid state, and at relatively low temperature, an enveloping body of metal also in solid state but at a relatively high temperature; allowing an equalization in the temperature ofthe blank so compounded; and subjecting the compound blank to a reducing operation.

2. The herein described method of forming compound metallic articles which consists in applying to a core of steel in solid state, and at relatively low temperature, a sleeve of copper in solid state at relatively high temperature; allowing the temperature of the blank so compounded to become equalized throughout; and subjecting the blank so compounded to a reducing operation.

3. The method herein described of forming compound metallic articles, which consists in shaping .upon a body of metal in solid state and at relatively low temperature, an enveloping body, of metal also in solid state, .but at relatively high temperature; allowing an equalization of the tem erature of the blank so compounded, and su jecting the compound-blank to a reducing operation.

4:. The method herein described of forming compound metallic articles which consists in shaping upon a body of metal while in solid state and at relatively low temperature, anenveloping body of metal also in.

solid state but at relatively high temperature; bringing the compound blank so formed to a temperature suitable for working and uniform throughout, and reducing the compound blank so'heated.

5. The herein describedmethod of forming compound metallic articles which consists in applying to a body of metal while the said bodyis in solid state and at relatively low temperature, an enveloping body of metal also in solid state but at relatively high temperature, bringing the blank so compounded to a uniform temperature throughout, and a temperature suitable for forging, and then elongating the blank so compounded by forging.

6. The herein described method of forming compound metallic articles which con sists in applying to a body of metal of relatively low coeificient of expansion while said body is in solid state and at relatively low temperature, an enveloping body of relatively high coeflicient of expansion also in l versely solid state, but at relatively high temperature, allowing an equalization in temperature of the blank socompounded and bring-' sistsin applying to a core of steel in solid state, and at relatively low"temperature,-a

sleeve of copper in solid state and at relativel" hi h ternerature'; allowing the tom perature of'the lank so com ounded to become equalized throughout, s aping one of the two component. bodies to contact with the other of the two bodies over surfaces extending transverse to the general length of the compound blank as a whole; heating said compound blank; and subjecting it to a reducing operation.

8. The method herein described of forming compound metallic articles which consists in applyin to a core of metal of relacient of expansion an en'- tively low coe of a metal of relatively high velo ing body coe cient of expansion, and bringin ploire 0 es tions of one of the two com onent into contact with portions of t e other body over surfaces which.'extendtransversely to the eneral length of the blank so compound-.

ed; eating such jecting it to a reducing operation,

'I In testimony whereof I have hereunto set my hand.

Witnesses: I

L. McGnnw RALPH V.

compound blank; and sub CHARLES w. Davis. 

